There's so much more we need to know.
For it to actually give some information, we need to know how & why these 4 care homes were picked.
We need to know what their practises were compared to others. Very difficult because they aren't going to admit if they had poor practices.
You would also need to know what type of care home they were, what the average age of residents, medical conditions etc.
Because right now, that could simply mean these 4 homes were terrible at handling the situation. Or it could mean one home didn't really do anything.
You would also need to do a separate study of other care homes to compare.
It also needs to be peer reviewed.